The paper covered preparations and characterisations of Ni-Ga based catalysts including Ni-Ga alloy, Ni-Ga/mixed oxides, Ni-Ga/ mesosilica and Ni-Ga-Co/mesosilica for synthesis of methanol from direct reduction of CO2 under hydrogen. The Ni-Ga alloy and Ni-Ga/ mixed oxides were prepared by metal melting method established at 1500oC and co-condensation-evaporation method at 80oC for 24 hours, respectively. The Ni-Ga/mesosilica and Ni-Ga-Co/mesosilica catalysts were both prepared by wet impregnation method at room temperature for 24 hours. The dried white powders obtained from the co-condensation-evaporation and the impregnation procedures were contacted with NaBH4/ethanol solution for reducing metal cations to alloy state at room temperature. Investigations on conversion of CO2 showed that the Ni-Ga/mesosilica and the Ni-Ga-Co/mesosilica catalysts behaved as the best candidates for the process when showing its high conversion of CO2 and selectivity of methanol at high pressure of 35 bars. Especially, the Ni-Ga